<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <link rel="stylesheet" href="../js/bootstrap4.3.1/bootstrap.min.css">
    <style>
        div {
            border: 1px solid #ccc;
        }
    </style>
</head>

<body>
    <main class="container-fluid">
        <div class="row">
            <div class="offset-md-2 col-md-4 mt-2">测试块1</div>
        </div>
    </main>
</body>

</html>